"The ozone on the West Coast in a few years will be controlled not by
California and Oregon,"Schnell says. "It will be controlled by China."
The incoming pollution bucks a U.S. trend toward cleaner skies and
water.

Mercury is especially suited for long-distance travelbecause at the
smokestack in elemental form, it's insoluble. By the time it reaches the
West Coast, however, some of the mercury has transformed into a
reactive gaseous material that dissolves in Western Oregon's wet
climate. It washes into the river, where microbes convert it into a form
that further concentrates in fish.

Hope was struggling to account for all the Willamette's mercury
sources before he encountered Dan Jaffe, an atmospheric and
environmental chemistry professor at the University of Washington at
Bothell. Jaffe and other scientists were detecting Asian pollutants in
monitors atop Mount Bachelor and Cheeka Peak, on the Olympic Peninsula.Urban carcinogen levels

The monitors regularly record levels of airborne carcinogens
equivalent to those of a major city, says Staci Simonich, an Oregon
State University researcher. In April 2004, instruments mounted atop
Mount Bachelor's Summit Express ski lift intercepted an enormous Asian
plume laced with mercury and ozone. The fine-particle concentration hit
about 20 micrograms per cubic meter, compared with the federal
air-quality standard of an average 65 micrograms during a 24-hour
period.

"The air we saw on that day was comparable to a moderately bad day in
Portland," says Jaffe. "When you consider that that air has traveled
thousands and thousands of miles, it's pretty amazing really." Jaffe
calculated that Asia emits 1,460 metric tons of mercury a year, twice as
much as previously thought.

To be sure, concentrations of foreign pollutants in Oregon are
minimal compared with federal air-quality standards. On an average
spring day in the Northwest, the overall sulfate concentration reaches
just 0.72 micrograms per cubic meter, says Colette Heald, a University
of California at Berkeley researcher. About one-quarter of the average
sulfate level comes from Asia, Heald says.

But the DEQ's Hope realized that when fallout occurs across an area
as large as the Willamette's 11,500-square-mile watershed, low
concentrations add up. He identified the river's mercury sources for a
study published in the international journal Science of the Total
Environment."...

Mercury acts on the central nervous system and can reduce mental
ability, making kids shy, irritable, and slow to learn, and causing
tremors and visual disturbances. Children under 7 should not eat more
than a single 4-ounce portion of nonmigrating fish every seven weeks,
while women of childbearing age should eat no more than one 8-ounce
portion a month.

The DEQ has a mercury cleanup plan for the Willamette that will take
decades. But "you throw in the global contribution," says Dave Stone,
Oregon public health toxicologist, "and it does become that much more
complex." Oregon, which has 14 fish advisories for mercury, has not been
able to lift one.

Impact on cleanupThe added mercury from abroad, coupled with Oregon's high natural
levels, could concentrate pressure on local emitters under the DEQ's
cleanup plan. Weyerhaeuser, for example, has more than 15 plants in the
watershed. "We're concerned to the extent that we have to do something
that won't matter," says Marv Lewallen, Weyerhaeuser Oregon
environmental affairs manager.

Cliff says China's growing contribution will complicate U.S. efforts
to meet annual average emissions standards. "As you try to reduce
particulate pollution from local and regional sources, you're only
reducing to some background level," Cliff says. "The concern is that as
China continues to expand, that background level will only tend to
increase."

A recent court decision raises the possibility that foreign firms
could be held liable for polluting the United States. A 9th U.S. Court
of Appeals panel ruled that Teck Cominco Ltd., a company that discharged
heavy metals and slag in the upper Columbia River in Canada, must pay
to clean up a downriver stretch in the United States.

Scientists are frustrated by a lack of data from Asia, where
factories often aren't requiredto report what they emit, says Richard
"Tony" VanCuren, a UC Davis applied-sciences researcher.

Smog, also known as ground-level ozone, is harmful to human health, because it can exacerbate asthma attacks and cause difficulty breathing. It also harms sensitive trees and crops.
It’s different than the “good” ozone up in the stratosphere, which
protects life on Earth from the sun’s harmful ultraviolet rays.

Scientists measured ozone levels recorded at
springtime for the past 25 years in 16 national parks in the western
U.S., including Yellowstone, Yosemite and Grand Canyon. The parks’ locations farther away from cities,where smog is typically expected, made them ideal spots for the study.